[1.3.0] OPT Space Plane v2.0.1 - updated 29/07/2017

[Callistoan]

3 hours ago, JadeOfMaar said:

@RaiderMan The design of the spaceplane may objectively be very bad. Answering someone's query for design help with an autopilot mod is not the way to go. It does not help the person to design their craft better, and if the design is poor enough then the autopilot will miserably fail.

@Callistoan Your spaceplane design was objectively bad. I removed the forward service bay as it contributed the most to omni-directional body lift (see light blue aero effect lines in album) and replaced it with a down-facing extra deployment bay. I raised the main wings to raise the CoL to fortify the plane against flying upside down, and added some loaded Ore tanks to control the CoM (since these wings are heavy). I then added some down-facing stabilizers to increase very badly needed yaw control (see omni-directional lift problem), and I removed the elevons from the underside of the aerospike as they lower the CoL and make the plane want to fly upside down. Also, flaps around an aerospike sounds wrong to me-- especially when the aerospike rightfully has gimbal and lots of it.

Finally, I added some stabilizers (as canards or forward flaps) to increase the plane's forward pitch authority which is also needed very badly. Note, I keep these wings dry. I don't like clipping things into loaded tanks, and the wet mass CoM offset is not worth the dV. Pitch authority lies equally in an aircraft's ability to force its tail up, and its ability to force its nose down to resist flipping out at high AoA. Either have canards or (preferred) have lots of rear control surface area near the CoM. I no longer needed to empty my RCS to guarantee a stable reentry.

It's no longer the shuttle you may dream of...but it's a stable one and not that much bigger. You could skip the down-facing yaw stabilizers and pack more RCS fuel or more sideways RCS thrust to compensate.

Imgur Album

Thank you so much omg! This is my first spaceplane (since I wanted to use the pack with it), and I really appreciate the constructive criticism. Btw, how do you add the ore tanks to the wings? I'm still not sure how you do that? Also, how much fuel do you suggest I keep in the tanks.

Edited September 27, 2019 by Callistoan

[JadeOfMaar]

You're welcome. I didn't add the Ore tanks to the wings. I put them in the rear deployment bay, towards the bottom, and offset them down enough so that KER measures near zero thrust torque. I also made sure that the wheels are offset down enough and the wings not offset too high, all for that zero thrust torque. These things can be quite delicate.

[Cloakedwand72]

My game is having trouble loading with your OPT mod its stuck on the loading screen when it says OPT_Legacy parts sage engine.

[JadeOfMaar]

12 minutes ago, Cloakedwand72 said:

My game is having trouble loading with your OPT mod its stuck on the loading screen when it says OPT_Legacy parts sage engine.

Install Community Resource Pack.

The SAGE and SURGE engines require IntakeAtm resource which is present in any planet's atmosphere, representing atmosphere usable as working fluid or reaction mass regardless of having Oxygen or not. Those engines can operate in any atmosphere, not just Kerbin and Laythe.

[Callistoan]

@JadeOfMaar In the future, how can I better build spaceplanes?

[JadeOfMaar]

On the front page of the forum there's a block on the right called Featured Streamers. When you see the name Rocketology appear in there, go to his Twitch channel and ask him. He makes it his business to teach proper aircraft design.

[RaiderMan]

-glares at keyboard- I KNOW I typed more than that...I'm not in the habit of just chucking a mod at every problem, such as an issue to do with the design causing flight instability for example..

to be fair...some of the super shuttles I've flown that a friend, K1, designed, are seriously unstable during reentry if the monoprop distribution is left alone, a simple fix in that case is to just redistribute the fuel to achieve the desired performance..for example, his get REALLY light in the nose during initial entry phase, so I shove the monoprop all foreward, then once in atmo proper, I start moving it all back cause at that point I WANT the lift. I may even light the oms engines to eek out some more speed and lift at times.

[JadeOfMaar]

@RaiderMan Heh. It's the best thing when something steals focus and makes you type into nothing. At least, I had anticipated you'd know a thing or two better and could have had advice to share. I'm sad now that I didn't get to see it. And that is a very interesting situation-- the shuttles and their MonoProp balance.

[RaiderMan]

I've even used this to great effect with capsules, I'll shed rcs I'm not expecting to use, by dumping it into the service module.

that said, @Callistoan I would propose adding canards to the forward fuselage, and perhaps lengthen it a hair if possible, to accomodate those canards.

please mind your fuel distribution during reentry, as while SAS can cope with ALOT, if your fuel load isnt balanced, no matter how much power SAS throws at it via rcs thrusters, you're going to have issues.

also consider experimenting with alternative rcs thrusters, as the 'oreo thrusters' I noticed you using may not be powerful enough to cope with the forces acting on the airframe.

side note...I typically overdo it with thrusters until I know how its going to run...so I'll put a set of two on the nose, two on the tail, and two on the wings, and then throw things at the wall and see what sticks.

 @JadeOfMaar is that what you meant? XD.

now..bog standard space shuttles, thats a case of russian roulette.. darned if you do, darned if you dont, with stability assist mods...

[JadeOfMaar]

@RaiderMan Yep. That answer is sufficient. And I'd call those RCS blocks "shirt buttons" lol!

OPT has a small array of RCS thrusters to use, all of which are decently powerful and fit for use on heavy spaceplanes. But there's no compact 5-way thruster.

[RaiderMan]

you also have to mind reentry...as I've had thrusters cook off and explode off my craft because I wasnt careful to shield them properly or use specially designed thrusters.

it takes some jiggery pokery to imitate a 5 way on a space plane...I've seen people stick thrusters on the vertical tails just cause there was no other spot for roll control thrusters on the stern.

[gilflo]

17 hours ago, JadeOfMaar said:

@gilflo If you're not already using OPT Reconfig I highly recommend you do. It makes OPT more compatible with popular mods, re-tunes the engines to have more believable behaviors and fixes many lift/drag issues. There is a cryo tanks patch in there but it requires you to install Nertea's Cryo Engines. By popular demand this patch does not add the boiloff management to OPT.

If you're interested I started on a config to make OPT engines run on LH2 as well. It would be nice to have someone to test it and give feedback.

 

I am using OPT reconfigurations. what I am looking for is OPT tanks cooled for use of Cryo engines from the Cryogenic engine mod or from the Tor Tech mod.

I am working on double Stratoalauncher to launch a  Spaceplane on RSS. it's a big challenge to reach orbit at more than 7500m/s. I use OPT mod for Stratolauncher . I would like to use OPT mod for space plane, but as it's mainly running on LH2 I need Cryo cooled tanks from Cryogenic tank mod. If there was a option for cooling LH2 on OPT tanks I would use OPT mod to design my space plane with  engines running on LH2 from Cryogenic engine mod or Tor Tech mod

[Cloakedwand72]

6 hours ago, JadeOfMaar said:

Install Community Resource Pack.

The SAGE and SURGE engines require IntakeAtm resource which is present in any planet's atmosphere, representing atmosphere usable as working fluid or reaction mass regardless of having Oxygen or not. Those engines can operate in any atmosphere, not just Kerbin and Laythe.

Thanks.

[JadeOfMaar]

@Cloakedwand72 You're welcome.

@gilflo Ah. Well insert the ModuleCryoTank module into GameData/OPT_Reconfig/CRP/OPT_B9PS_Cryo.cfg before the line that says "// Cabins" so that it looks like this. Please do not accidentally duplicate the existing stuff around it. When you restart KSP, all OPT tanks will be applied to.

// Apply subtypes
@PART:HAS[#manufacturer[OPT*Division],@MODULE[ModuleB9PartSwitch]]:NEEDS[B9PartSwitch,CryoEngines,!Pathfinder]
{
	MODULE // The cooling/boiloff module
	{
		name =  ModuleCryoTank
		// in Ec per 1000 units per second
		CoolingEnabled = True
		BOILOFFCONFIG
		{
			FuelName = LqdHydrogen
			// in % per hr
			BoiloffRate = 0.05
			CoolingCost = 0.05
		}
		BOILOFFCONFIG
		{
			FuelName = LqdMethane
			// in % per hr
			BoiloffRate = 0.005
			CoolingCost = 0.02
		}
	}
	// Cabins
	@MODULE[ModuleB9PartSwitch]:HAS[#moduleID[OPTcabin]]
	{
		SUBTYPE
		{
			name = LH2
			tankType = OPTLH2
			title = OPT LH2
		}
		SUBTYPE
		{
			name = Hydrolox
			tankType = OPTLH2O
			title = OPT Hydrolox
		}
		SUBTYPE:NEEDS[CryoTanksMethalox]
		{
			name = Methane
			title = #LOC_CryoTanks_switcher_fuel_methane
			tankType = LM
		}
		SUBTYPE:NEEDS[CryoTanksMethalox]
		{
			name = Methalox
			title = #LOC_CryoTanks_switcher_fuel_methalox
			tankType = LMOx
		}
	}

I would really like to know how Thor Tech is involved with Cryo Engines. I assume you've patched its LiquidFuel engines to burn LH2.

Edited September 27, 2019 by JadeOfMaar

[gilflo]

Thank you, I'll do that

[Callistoan]

@JadeOfMaar Hey, I'm still having problems. I'm also having issues that when I launch the spaceplane, it launches like 100 m above the ground. What am I doing wrong here?

[Stone Blue]

3 hours ago, Callistoan said:

I'm also having issues that when I launch the spaceplane, it launches like 100 m above the ground. What am I doing wrong here?

What do you mean? Like, it *spawns* high above the runway, and drops down to the ground, before you can even do anything in the flight scene?

If so, that sounds like the 1km spawn bug, usually caused by a collider problem with one of the parts used in the craft. The Humpback 7m Cargo Tail from Legacy is known to do that. I dont remember if any of the OPT Main parts do it and need fixing. That inline cargo bay you have in the center of the craft would be my guess as the culprit.

If this is what you are seeing, you can try installing the World Stbilizer mod, until, and if ever the parts themselves get updated with a fix.
 

 

[JadeOfMaar]

@Callistoan

Initial analysis (pure assumption with some rules of thumb for design)

I'm not sure what else I can advise you on as I gave you an extensive report already. My guess is that either your canards are too far forward (bringing the CoL too near to the CoM and making it too easy to pitch or roll) or your CoM moves behind the CoL as your fuel nears empty. Always take the time to check the CoM when empty before you launch, and rotate the craft by its root part in the SPH to see how the CoL will move around. You may still be lacking in yaw control too. It's just a personal issue for me but I don't like having all my yaw control pieces only above the CoM.

From what I know, the large vertical fin's purpose is actually not to help you yaw but to enable "coordinated turns" (see: Coordinated Flight: flying and turning without sideslip), so by consequence you only think you have yaw control but actually have too little or none, and no power to control the "phantom yaw" that OPT planes sometimes experience.

Professional analysis (after test flights)

After replicating your craft I saw a perfectly placed, perfectly static CoM and its steering (pitch) and gliding ability were quite fine. Its handling was great as long as I set my roll degree (as close to zero in this case) and never touch it after, and keep my pitch angle within 20 deg of prograde. The plane has an annoying long moment of inertia with roll and will tend to flip out when the roll leads to sideslip (see "coordinated flight"). With this kind of handling I must conclude that you're lacking a lot in pilot skill as this plane flies very, very nicely once you know how to recognize and anticipate its handling. Again, I shall point you to, and link him this time, @Rocketology Rocketology (Twitch stream). He streams KSP very regularly and he makes it his business to teach piloting and good aircraft design. I have him to thank for my ability to teach you through this post!

Test flight album #2

Once I understood the handling I didn't need RCS at all.

 

I think I would lose the stock elevons though. They may be deflecting the wrong way and can be redundant and useless with mustache canards if you don't know and use the concept of leading edge Slats and trailing edge Flaps.

As for the 1km spawn problem, the mod linked above is the solution.

Edited September 30, 2019 by JadeOfMaar

[Nio9345]

I have a huge problem. For some reason almost all wings have 0 lifting capability, only some wiglets work but also those won't give a lot of lift. I have OPT Main, OPT Legacy and OPT Reconfig latest updates outside of CKAN.

[JadeOfMaar]

8 hours ago, Nio9345 said:

I have a huge problem.

Assuming you have FAR (which I doubt. I don't see the app button for it) you may have the "other" OPT FAR config. If that one and the FAR config in OPT Reconfig are present, they cause conflict. I also suspect you might have TweakableEverything which is very incompatible with OPT for reasons.

If you don't have either of these, send me your KSP.log, your KSP/GameData/ModuleManager.ConfigCache, and the folder: KSP/Logs/ModuleManager/, preferably all in a nice zip file.

If you don't know how to share logs there's a red button in my signature.

[Nio9345]

13 hours ago, JadeOfMaar said:

Assuming you have FAR (which I doubt. I don't see the app button for it) you may have the "other" OPT FAR config. If that one and the FAR config in OPT Reconfig are present, they cause conflict. I also suspect you might have TweakableEverything which is very incompatible with OPT for reasons.

If you don't have either of these, send me your KSP.log, your KSP/GameData/ModuleManager.ConfigCache, and the folder: KSP/Logs/ModuleManager/, preferably all in a nice zip file.

If you don't know how to share logs there's a red button in my signature.

Thank you for the reply. So after reading your reply I remember I installed FAR and then removed it before I used it at all. I don't know if it did anything but I tried and "disabled" OPT_FAR2.cfg and it seems to do something. I don't know if temporarily fixed something so I uploaded the files you requested.

 

https://www.dropbox.com/s/96jtn13n4ylbawn/KSP_LOGS.7z?dl=0

[JadeOfMaar]

@Nio9345 The folder FerramAerospaceResearch exists in your GameData folder. Just being there is enough for FAR patches to trigger. Delete it.

[Nio9345]

34 minutes ago, JadeOfMaar said:

@Nio9345 The folder FerramAerospaceResearch exists in your GameData folder. Just being there is enough for FAR patches to trigger. Delete it.

Ok. I think I will double check CKAN's operations from now on since it didn't delete the folder when I disabled it

 

Also thanks a lot

 

Update 1:

Now for some reason all engines require Liquid Hydrogen instead of Liquid Fuel.

Edited October 7, 2019 by Nio9345

[JadeOfMaar]

You're welcome.

1 hour ago, Nio9345 said:

Update 1:

Now for some reason all engines require Liquid Hydrogen instead of Liquid Fuel.

Lol! Well... I released that change a moment ago... it complements/completes the OPT CryoTank option(s). If you don't like it, delete OPT_Reconfig/CRP/OPT_CryoEngine.cfg and let me know. You shouldn't need to add more tanks to your plane.

 

[Nio9345]

19 hours ago, JadeOfMaar said:

You're welcome.

Lol! Well... I released that change a moment ago... it complements/completes the OPT CryoTank option(s). If you don't like it, delete OPT_Reconfig/CRP/OPT_CryoEngine.cfg and let me know. You shouldn't need to add more tanks to your plane.

 

Ok new problem ... All cockpits and connectors are treated as wings and they mess the CoL really bad and the elerons and lift surfaces freak out and when I try to go up the wings go down and I crash.